Enabling Quotas for Firefox Sync

This generally won’t affect users, but we wanted to be open about a change that will be deployed soon for our production servers. Essentially, we’re going to be defining a per-user disk quota for Firefox Sync, with the initial limit being 25 MB of data per user. For the vast majority of users, this will be completely invisible, since the typical user uses a lot less. (I’m a very heavy browser user, and I’m at around eight megabytes of usage.) We’ve attempted to answer some of the expected questions below, but anything else can go in the comments.

Why implement quotas?

We want to keep Firefox Sync as a free service for everyone. In order to make this viable, we have to take steps to control costs and prevent abuse. Implementing a reasonable default cap on disk usage is an obvious step in that direction. We believe the initial default will be sufficient for nearly all users.

How much of my data will I be able to sync?

In general, as much as you’re already syncing. Based on our current usage statistics, this quota will be enough for more than 99.9% of our users. The average user uses about 1 MB of data, with an average of 83 bookmarks, 11 passwords, and 1500 history items. Even around the 90th percentile of users, the disk usage is under 6 MB, with around 700 bookmarks, 12000 history items, and 100 passwords.

Can I get more space?

While the specifics have yet to be determined, one of the things we’re working on is a means to allow specific users to have a higher quota. In the meantime, it is already possible to request a quota increase via the Mozilla Services Account web page. We don’t yet have a timeline for if/when these requests will be fulfilled, but we’re using those inputs to help understand why users would need more quota to inform future designs.
Alternatively, for those more technically inclined, our server code is open source and can be installed on a server of your choice. For more information on this, please see the setup instructions.

What happens if I run out of space?

When a user passes the “warning” threshold (we expect to set this to 20 MB), the server will pass this information back to the client, so users get warned before they are unable to write to the server. If a user ignores these warnings and actually hits the cap, they will be unable to write any additional data to the server, and they will see Sync errors informing them of the problem. Firefox has UI that controls what type of data to sync, and how much each type of data is using. Users will be able to disable individual sync engines and free up space, if necessary.

— mconnor, on behalf of the Services team

10 responses

  1. Brownout wrote on :

    Are you aware that with the new “smart” history retention algorithm (http://blog.bonardo.net/2010/01/20/places-got-async-expiration) you can easily end up with months of history retained in your Firefox profile?
    Someone with 1500 history items and 83 bookmarks is simply not using Firefox as their primary browser and doesn’t really need to sync them across machines. (Btw, how do you know how many bookmarks someone has saved, I thought everything was encrypted.)
    I’m not saying that user quotas are inherently bad, but, *please*, can you talk to each other when making such design decisions? Right now I can’t even check my quota usage in FF 4.0.1, I get “Could not retrieve quota information”

  2. Netsurfeur wrote on :

    I just checked my sync quota usage (as reported by «Display quota» in Sync preference) and I am using 14.1 MB, 13.7 MB being my history.

    I have erased all my history, forced a new sync and checked again. Quota usage has not changed, it is still 14.1 MB.

    How can I reduce my sync data usage ?

  3. geeknik wrote on :

    Interesting, I just looked and I’m using 15.7MB. =)

  4. mconnor wrote on :

    @Brownout: Yes, I’m absolutely aware of it. In fact, I was one of the people who advocated heavily for that change. 🙂

    However, Sync does not actually keep all of your history on the server, just the sites visited in the last 60 days, so this change won’t impact quota usage.

    @Netsurfeur: erasing history locally doesn’t currently wipe the server, see bug 578694. If you uncheck history sync, we’ll clear history data from the server on the next sync.

    @geeknik: you’re an outlier, indeed!

  5. tom jones wrote on :

    the only way for anyone to reach 25mb is with big history (i have tens of thousands of bookmark, and they are only 2mb), so i suggest a refinement:

    * assign lower priority to history, and enable “partial” history sync.

    for example, if i have reached my quota, only store “most recent X months of history”, however much that may be to fill the quota, but *always* allow me to keep storing bookmarks and passwords (at the cost of deleting old history entries).

    i like to have years worth of history, but i am ok if only part of that can be synced.

    1. mconnor wrote on :

      As noted just now, we don’t actually store all history, just the last 60 days worth at max. So… we’re already there. 🙂

  6. Netsurfeur wrote on :

    Thank you.
    I have unchecked history, synced, checked history and synced again. My quota usage is now 587 KB.

  7. Robert O’Connor wrote on :

    Man, if geeknik is an outlier, then what does that make me? I just checked mine and sync was reporting 33.2 MB.

    1. mconnor wrote on :

      You’re in the 0.01% of users who have that much history. Or we haven’t been running cleanup in production yet so some of that is from before we enabled TTLs on records (possible, will check into it!)

  8. Robert O’Connor wrote on :

    I use to have Firefox set to retain history for the maximum possible number of days when that was configurable. I might assume that to be a contributing factor.